1. Field of the Invention
The present invention relates to deicing systems, and, more particularly, to a roof and gutter deicing system.
2. Description of the Related Art
Ice dams forming near the outer edges, or "eaves," of a roof and extending into the gutters are a significant source of damage to a building. Ice dams form when snow on an inner or middle section of a roof melts and the meltwater flows down to the outer section of the roof, where it then refreezes into ice. The heat from within the building conducts through the roof to melt the snow on the middle portion of the roof. However, the outer edge of the roof extends outwardly beyond the outside wall of the building, and therefore is not heated by the heat from within the building. Thus, the melted snow from the middle portion of the roof refreezes and accumulates on the outer edge portion of the roof and in the gutters, thereby forming ice dams. Another possible cause of ice dams is the heating of the dark shingles when exposed to sunlight. Snow on the roof slides down to the gutter, where it abuts the gutter, thaws and refreezes. The freezing of the meltwater eventually builds up into an ice dam.
Such ice dams are known to cause leaks in roofs by allowing water to enter underneath the shingles of the roof and expand upon refreezing, thereby forcing the shingle away from the other shingles on the roof. The weight of ice dams can also tear a gutter away from the roof and/or soffit, thereby requiring costly repairs.
It is known to attach a heater wire to the outside surface of the outer edge portion of the roof. The heater wire may also extend along the gutter and through the downspout in order to maintain an open drainage path for melting of the frozen precipitation.
Snow and ice melting systems commonly employ automatic ON/OFF controls that operate heaters only while required to minimize energy consumption and operating costs. Typically, the automatic ON/OFF controls sense ambient moisture and temperature. However, it is also possible for the automatic ON/OFF control to be in the form of a thermostat which only senses ambient temperature. Heaters operate at ambient temperatures below a threshold--usually 38.degree. F. while ambient moisture is present and for a period of time thereafter to clear accumulated snow and ice. Optionally, the automatic ON/OFF control may inhibit heater operation at temperatures too low for effective melting, e.g., below 17.degree. F. Status indicators and a manual control and test switch are typically included in the same package with such automatic ON/OFF controls.
In order to reduce costs and simplify installation, it is known to install the automatic ON/OFF control package close to the heating device itself. A problem with installing the control package in close proximity to a roof heater is that it is then difficult to observe the status indicators and to test deicing system performance with the manual control and test switch.
Ground current is the difference between the outbound and return heater currents. The U.S. National Electric Code requires using a ground fault circuit interrupter (GFCI) on all snow and ice melting circuits. The GFCI interrupts heater current if the ground current exceeds a predetermined limit; usually 30 milliamperes. The GFCI requires manual reset after tripping. This preserves safety by not restarting heater operation during intermittent ground leakage current that may occur in wet locations.
Independent of the heater fabrication method, ground current can flow due to a heater failure caused by a manufacturing defect, corrosion, wear and tear or mechanical damage. Excessive ground current causes the dual safety problems of fire and shock hazard. An electrical shock hazard can also occur whenever ground current flows since its path to earth ground is usually not predictable. Thus, a GFCI is required to be incorporated into snow and ice melting electrical circuits. It is known to install a residential GFCI in a knockout box adjacent to the deicing system. Again, a problem is that a GFCI disposed next to a roof deicing system is difficult to access for purposes of resetting and/or testing the GFCI.
What is needed in the art is an apparatus for melting snow on the outer edge of a roof that does not require the user to physically access the apparatus in order to periodically reset or test the ground fault circuit interrupter or to monitor the status of the heater.